Berlin 2001 – wissenschaftliches Programm

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AMPD: EPS AMPD

AMPD 9: Sitzung 9

AMPD 9.5: Vortrag

Freitag, 6. April 2001, 15:00–15:25, H105

High–Accuracy Determination of the Atomic Mass of the Electron — •W. Quint¹, T. Beier¹, H. Häffner², N. Hermanspahn², S. Karshenboim³, H.-J. Kluge¹, G. Marx¹, T. Valenzuela², J. Verdu¹, and G. Werth² — ¹GSI Darmstadt, Germany — ²University at Mainz, Germany — ³Mendeleev Institute for Metrology, St. Petersburg, Russia

We report on a high-accuracy determination of the electron mass in atomic units (u). Our mass determination is based on the measurement of the Larmor precession frequency of the bound electron in the hydrogen–like carbon ion ¹²C⁵⁺. In our experiment, a single ¹²C⁵⁺ ion is stored in the magnetic field of a Penning trap [1,2]. The Larmor frequency of the bound electron is measured by inducing quantum jumps between the two spin states (spin up and spin down) of the electron. The magnetic field strength is calibrated via the cyclotron frequency of the ¹²C⁵⁺ ion. Our value for the electron mass m_e = 0.000 548 579 909 2 (5) u is the most accurate measurement of the electron mass so far. Also, we deduce a new value for the electron–proton mass ratio.

[1] N. Hermanspahn et al., Phys. Rev. Lett. 84, 427 (2000).

[2] H. Häffner et al., Phys. Rev. Lett. 85, 5308 (2000).